|Publication number||US8186327 B2|
|Application number||US 12/364,007|
|Publication date||May 29, 2012|
|Priority date||Feb 2, 2009|
|Also published as||CN101818669A, CN101818669B, DE102010006626A1, US20100192898|
|Publication number||12364007, 364007, US 8186327 B2, US 8186327B2, US-B2-8186327, US8186327 B2, US8186327B2|
|Inventors||Ben Xuehai Ni|
|Original Assignee||Ford Global Technologies|
|Export Citation||BiBTeX, EndNote, RefMan|
|Patent Citations (17), Referenced by (5), Classifications (6), Legal Events (2)|
|External Links: USPTO, USPTO Assignment, Espacenet|
1. Field of the Invention
The present invention relates to an internal combustion engine lubrication system in which maximum pressure within the lubrication system is controlled by a dual mode pressure limiting valve.
2. Related Art
Pressure-lubrication has been used with automotive internal combustion engines for many years. Typically, a single pressure relief valve is used to limit the maximum pressure developed by an oil pump. The relief pressure is usually set at a fairly high value, in order to assure that the engine receives adequate lubrication in all operating regimes from idle to maximum speed-load operation. Unfortunately, this causes the lubrication pump's energy consumption to be higher than would otherwise be ideal, because in many operating regimes, only a reduced volume and pressure of oil is required by the engine.
US Patent Publication 2002/0083915 discloses a system in which a minimum oil pressure is established by a mechanically operated valve, with an electrically operated valve positioned in the mechanical valve's relief port such that the system pressure may be increased through closure of the electronically operated valve. This system suffers from the drawback that the electrically operated valve does not have a fail-safe position. In the event that the electrically operated valve fails in an open position, only minimal oil pressure would be available to sustain the engine, and such minimal oil pressure would undoubtedly be inadequate to support the engine during high speed and load operation. On the other hand, if the electrically operated valve fails in a closed position, the resulting excessive oil pressure may damage or destroy the engine by causing the oil filter to rupture, with a consequent loss of all oil overboard. In other words, any failure of the electronic valve could lead to engine failure. In another vein, the reliability of the electrically operated valve is compromised because only unfiltered oil flowing from the oil pump passes through the valve, and foreign matter carried by the unfiltered oil may cause the valve to stick or wear excessively.
It would be desirable to provide an internal combustion engine lubrication system in which an engine is reliably protected with a redundant high pressure mechanical relief valve, combined with the capability of reducing the oil pressure so as to promote fuel economy improvement during operating regimes in which maximum oil pressure and flow are unneeded.
According to an aspect of the present invention, a lubricating oil supply system for an internal combustion engine includes an oil reservoir and an oil pump for pressurizing oil from the reservoir. A lubrication distribution network is connected with the oil pump. A primary pressure relief valve is connected to the distribution network downstream from the oil pump. The primary pressure relief valve limits oil pressure within the distribution system to a maximum permissible value. A pilot-controlled, dual mode pressure relief valve, operatively connected with said distribution network downstream from said primary pressure relief valve, selectively controls the pressure within said distribution network to a minimum pressure which is less than the highest pressure produced by the primary pressure relief valve.
According to another aspect of the present invention, a dual-mode, piloted pressure relief valve, operatively connected with an oil distribution network downstream from a primary pressure relief valve, controls the pressure within the distribution network by returning oil from the distribution network to the oil reservoir, with the piloted pressure relief valve having a first operating mode, in which a pilot valve is energized, wherein the piloted pressure relief valve limits the pressure within the distribution network to a first pressure which is less than the highest pressure produced by a primary pressure relief valve, and a second operating mode, in which the pilot valve is not energized, wherein the piloted pressure relief valve limits the pressure within the distribution network to a second pressure value which is greater than the first relief pressure.
It is an advantage of a lubricating oil supply system according to the present invention that engine fuel consumption may be reduced by minimizing parasitic losses associated with an engine driven lubricating oil pump, while at the same time safeguarding the engine's integrity, by using a piloted pressure relief valve having a normally closed pilot valve, such that if the pilot valve operating system fails, the engine oil pressure will be maintained at a safe level for all engine operating modes and regimes.
It is another advantage of a system according to the present invention that the piloted pressure relief valve of the present invention may be mounted externally upon the engine, as opposed to the known conventional practice of mounting of relief valves deep inside an engine, such as in an engine oil pump, rendering such valves relatively inaccessible for service purposes.
It is yet another advantage of a system according to the present invention that the piloted pressure relief valve of the present invention may be located downstream from an oil filter, thereby protecting the pressure controller from oil-borne contamination.
It is yet another an advantage of a system according to the present invention that the inventive piloted pressure relief valve has a dual mode feature, whereby the piloted valve may be used to limit maximum lubrication system pressure in the event that a primary relief valve fails in a closed position.
It is yet another an advantage of a system according to the present invention that flow of lubricating oil through an engine will not be diminished when the present dual mode valve is not operating in a pressure limiting mode.
Other advantages, as well as features of the present invention, will become apparent to the reader of this specification.
As shown in
The present lubricating oil supply system includes not only oil reservoir 14, oil pump 18, and lubrication distribution network 22, but also a primary pressure relief valve, 34, employed to limit the oil pressure within distribution network 22 to a maximum permissible value. In other words, pressure relief valve 34 clips the oil pressure to a predetermined maximum value. This protects, for example, oil filter 38 from destruction were the oil pressure to be too high during cold operation at higher engine speeds.
The present system also includes a pilot-controlled, dual mode pressure relief valve, 60. Valve 60 is operatively connected with distribution network 22 downstream from primary relief valve 34 and preferably downstream from oil filter 38.
In the absence of any signal from controller 50, valve 60 functions as a normally closed pressure relief valve having a pressure setting which approximates the setting of primary relief valve 34. Thus, the lubrication system will function as shown in
In the condition illustrated in
Once control ball 100 has been displaced from its seat due to an overpressure episode, the pressure at the control side of operating plunger 82 decreases and operating plunger 82 opens to allow oil to flow into outlet passage 80. This condition is shown in
The operating mode depicted in
As shown in
Although oil is bypassed at a lower pressure by valve 60, adequate oil pressure is provided to cylinder head 26 and to crankshaft bearings 30 because valve 60 is opened by controller 50 only during the several operating regimes in which it is not necessary to provide maximum oil pressure to sustain appropriate engine life. In fact, in many operating regimes such as those characterized, for example, by operation at less than half of the engine's maximum load, oil pressure may be significantly reduced while still providing adequate lubrication to the engine.
Valve 60 is preferably mounted to an external surface of engine 10, such as an outer surface of cylinder block 28. Such external mounting is shown in
The foregoing invention has been described in accordance with the relevant legal standards, thus the description is exemplary rather than limiting in nature. Variations and modifications to the disclosed embodiment may become apparent to those skilled in the art and fall within the scope of the invention. Accordingly the scope of legal protection afforded this invention can only be determined by studying the following claims.
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|US20120240893 *||Dec 7, 2009||Sep 27, 2012||Tbk Co., Ltd.||Engine lubricating oil supply device|
|US20130092108 *||Apr 18, 2013||Ford Global Technologies, Llc||Method for Warming an Internal Combustion Engine, and Internal Combustion Engine|
|US20130343937 *||Jan 27, 2012||Dec 26, 2013||Magna Powertrain Inc.||Oil pump with selectable outlet pressure|
|U.S. Classification||123/196.0CP, 123/196.00S|
|International Classification||F01M1/04, F01M1/00|
|Feb 2, 2009||AS||Assignment|
Owner name: FORD GLOBAL TECHNOLOGIES LLC, MICHIGAN
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:NI, BEN XUEHAI;REEL/FRAME:022189/0157
Effective date: 20090130
|Oct 27, 2015||FPAY||Fee payment|
Year of fee payment: 4